1) Most of our efforts have been focused on exosomes as a source of biomarkers. Typically, exosomes are isolated from urine by differential centrifugation, including an ultracentrifugation step. We developed a simpler procedure to isolate urinary exosomes[unreadable] by using a nanomembrane ultrafiltration concentrator that allows low speed centrifugation to replace the ultracentrifugation step. This should facilitate the discovery and validation of exosomal biomarkers, especially in laboratories that do not have access to an ultracentrifuge.[unreadable] [unreadable] 2) Expanding our search for biomarkers, we used proteomic discovery methods to examine the liver during early and later stages of sepsis. As liver injury precedes kidney injury, and our data suggest that there may be passive and/or active communication between organs, we sought liver proteins that could predict and/or mediate kidney injury. We validated the most promising candidates by western blot, and were able to demonstrate the functional significance of one candidate, cyclophilin A, by using an antibody against its receptor CD147.[unreadable] [unreadable] 3) Markers for early diagnosis. We continue to use microarray and proteomic techniques to search for early biomarkers of ischemia/reperfusion-, nephrotoxic-, and sepsis-induced acute kidney injury. We have a few excellent candidates, including Fetuin A, that are being validated using our mouse and rat acute kidney injury models, as well as in AKI patients.